Numerous types of additives are used to improve lubricating oil and fuel compositions. Such additives include, but are not limited to dispersants and detergents of the ashless and ash-containing variety, oxidation inhibitors, anti-wear additives, friction modifiers, and the like. Such materials are well known in the art and are described in many publications, for example, Smalheer, et al, “Lubricant Additives”, Lezius-Hiles Co., Cleveland, Ohio, USA (1967); M. W. Ranney, Ed., “Lubricant Additives”, Noyes Data Corp., Park Ridge, N.J., USA (1973); M. J. Satriana, Ed., “Synthetic Oils and Lubricant Additives, Advances since 1977”, Noyes Data Corp., Park Ridge N.J., USA (1982), W. C. Gergel, “Lubricant Additive Chemistry”, Publication 694-320-65R1 of the Lubrizol Corp., Wickliffe, Ohio, USA (1994); and W. C. Gergel et al, “Lubrication Theory and Practice” Publication 794-320-59R3 of the Lubrizol Corp., Wickliffe, Ohio, USA (1994); and in numerous United States patents, for example Chamberlin, III, U.S. Pat. No. 4,326,972, Schroeck et al, U.S. Pat. No. 4,904,401, and Ripple et al, U.S. Pat. No. 4,981,602.
Many such additives are derived from carboxylic reactants, for example, acids, esters, anhydrides, lactones, and others. Specific examples of commonly used carboxylic compounds used as intermediates for preparing lubricating oil additives include alkyl-and alkenyl substituted succinic acids and anhydrides, polyolefin substituted carboxylic acids, aromatic acids, such as salicylic acids, and others. Illustrative carboxylic compounds are described in Meinhardt, et al, U.S. Pat. No. 4,234,435; Norman et al, U.S. Pat. No. 3,172,872; LeSuer et al, U.S. Pat. No. 3,454,607, and Rense, U.S. Pat. No. 3,215,707.
Such carboxylic acids can be prepared by thermally reacting an aliphatic hydrocarbon or halogenated aliphatic hydrocarbon with unsaturated acids or acid derivatives at temperatures above about 200° C. The hydrocarbon typically is an olefin polymer such as polypropene or polybutene having number average molecular weights generally above 200. The rate of conversion of such reactions, however, is low and attempts to improve the conversion rate by increasing the reaction temperature and/or using super-atmospheric pressure results in degradation of maleic anhydride to carbon dioxide, water and tar-like solids
Many carboxylic intermediates used in the preparation of lubricating oil additives contain chlorine. One technique which has been used for improving the conversion rate, particularly when using aliphatic hydrocarbon alkylating agents, involves carrying out the reaction in the presence of chlorine. In some instances, high temperatures and long reaction times still are required.
While the amount of chlorine present is often only a small fraction of the total weight of the intermediate, the chlorine frequently is carried over into the carboxylic derivative which is desired as an additive. For a variety of reasons, including environmental reasons, the industry has been making efforts to reduce or to eliminate chlorine from additives designed for use as lubricant or fuel additives. The matter of chlorine content in additives is discussed in numerous patents including U.S. Pat. Nos. 5,356,552; 5,370,805; 5,445,657 and 5,454,964.
Accordingly, it is desirable to provide low chlorine or chlorine free additives for use in lubricants and fuels. While hydrocarbyl group substituted carboxylic compositions of this invention may be prepared employing the use of added chlorine during the reaction, the (α,β-unsaturated carboxylic compounds used to prepare the carboxylic compositions tend to react more readily, and with less attendant generation of tar and other decomposition products than previously employed unsaturated carboxylic compounds such as maleic anhydride.
In industry, it is also desirable to have available a wide variety of reactants available to prepare compositions. Materials shortages, costs, etc. contribute to uncertainties in the industry. These uncertainties can be relieved when more than a limited number of types raw materials are available to a manufacturer. The compositions of this invention are prepared employing raw materials that are different from, and are not suggested by, traditionally used raw materials.